Perylene Diimide Based Fluorescent Dyes for Selective Sensing of Nitroaromatic Compounds: Selective Sensing in Aqueous Medium Across Wide pH Range

Article abstract of DOI:10.1007/s10895-015-1725-8

Water soluble perylenediimide based fluorophore salt, N,N′-bis(ethelenetrimethyl ammoniumiodide)-perylene-3,4,9,10-tetracarboxylicbisimide (PDI-1), has been used for selective fluorescence sensing of picric acid (PA) and 4-nitroaniline (4-NA) in organic as well as aqueous medium across wide pH range (1.0 to 10.0). PDI-1 showed strong fluorescence in dimethylformamide (DMF) (Φf = 0.26 (DMF) and moderate fluorescence in water. Addition of picric acid (PA) and 4-nitroaniline (4-NA) into PDI-1 in DMF/aqueous solution selectively quenches the fluorescence. The concentration dependent studies showed decrease of fluorescence linearly with increase of PA and 4-NA concentration. The interference studies demonstrate high selectivity for PA and 4-NA. Interestingly, PDI-1 showed selective fluorescence sensing of PA and 4-NA across wide pH range (1.0 to 10.0). Selective fluorescence sensing of PA and 4-NA has also been observed with trifluoroacetate (PDI-2), sulfate (PDI-3) salt of PDI-1 as well as octyl chain substituted PDI (PDI-4) without amine functionality. These studies suggest that PA and 4-NA might be having preferential interaction with PDI aromatic core and quenches the fluorescence. Thus PDI based dyes have been used for selective fluorescent sensing of explosive NACs for the first time to the best our knowledge.

Full text of DOI:10.1007/s10895-015-1725-8

J Fluoresc
DOI 10.1007/s10895-015-1725-8
ORIGINAL ARTICLE
Perylene Diimide Based Fluorescent Dyes for Selective Sensing
of Nitroaromatic Compounds: Selective Sensing in Aqueous
Medium Across Wide pH Range
1
2
2
1
P. S. Hariharan & J. Pitchaimani & Vedichi Madhu & Savarimuthu Philip Anthony
Received: 31 August 2015 /Accepted: 10 November 2015
#
Springer Science+Business Media New York 2015
Abstract Water soluble perylenediimide based fluorophore
salt, N,N′-bis(ethelenetrimethyl ammoniumiodide)-perylene-
have been used for selective fluorescent sensing of explosive
NACs for the first time to the best our knowledge.
3
,4,9,10-tetracarboxylicbisimide (PDI-1), has been used for
. .
Keywords Perylene diimide Fluorescent sensor Explosive
selective fluorescence sensing of picric acid (PA) and 4-
nitroaniline (4-NA) in organic as well as aqueous medium
across wide pH range (1.0 to 10.0). PDI-1 showed strong
fluorescence in dimethylformamide (DMF) (Φf=0.26
.
sensor Picric acid sensor
(
DMF) and moderate fluorescence in water. Addition of picric
Introduction
acid (PA) and 4-nitroaniline (4-NA) into PDI-1 in DMF/
aqueous solution selectively quenches the fluorescence. The
concentration dependent studies showed decrease of fluores-
cence linearly with increase of PA and 4-NA concentration.
The interference studies demonstrate high selectivity for PA
and 4-NA. Interestingly, PDI-1 showed selective fluorescence
sensing of PA and 4-NA across wide pH range (1.0 to 10.0).
Selective fluorescence sensing of PA and 4-NA has also been
observed with trifluoroacetate (PDI-2), sulfate (PDI-3) salt of
PDI-1 as well as octyl chain substituted PDI (PDI-4) without
amine functionality. These studies suggest that PA and 4-NA
might be having preferential interaction with PDI aromatic
core and quenches the fluorescence. Thus PDI based dyes
Developing fluorescent chemosensors have attracted signifi-
cant attention over the years because they not only help for
environmental screening of potentially hazardous chemicals
but also serve as diagnostic tool for medicinal field and mech-
anistic tool for understanding biochemical process [1–4]. The
simple operation, real time monitoring, fast response and high
sensitivity further enhanced the interest in the field [5]. Partic-
ularly, small organic fluorophore molecules are highly pre-
ferred since they often synthesized via straightforward reac-
tion, and importantly their solubility and structures can be
tuned chemically to enhance the sensing and selectivity [6].
Several fluorescent sensors for selective sensing of heavy met-
2
+
2+
2+
2+
−
al cations (Hg , Zn , Cd and Mg ) and anions such as F
and cyanide have been designed and synthesized [7–12].
Electronic supplementary material The online version of this article
Nitroaromatic compounds (NACs) such as nitrobenzene
(NB), 4-nitroaniline (4-NA), trinitrotoluene (TNT) and picric
acid (PA) are extensively used for several applications that
include dyes, insecticides and explosives [13–15]. NB used
as industrial solvents whereas TNT is commonly used explo-
sive chemical. PA has also been widely used as explosives and
on small scale it used as antiseptic and for the treatment of
burns [16]. Further PA has finds application in dye industries,
pharmaceuticals and chemical laboratories [17]. However,
contamination of NACs in water and soils are very serious
especially chemically sensitive animals and plants [18, 19].
It is noted that some of the NACs like PA and nitrobenzoic
(
doi:10.1007/s10895-015-1725-8) contains supplementary material,
which is available to authorized users.
*
*
Vedichi Madhu
madhu@karunya.edu
Savarimuthu Philip Anthony
philip@biotech.sastra.edu
1
2
School of Chemical & Biotechnology, SASTRA University,
Thanjavur 613401, Tamil Nadu, India
School of Science and Humanities, Department of Chemistry,
Karunya University, Coimbatore 641 114, Tamil Nadu, India

J Fluoresc
acids are highly water soluble. For example, exposure of PA to
humans can cause respiratory problems, damage liver, and
bladder tumor [20–23]. Therefore, it is of great importance
for detection and quantification of these toxic explosive NACs
that contaminate the environment or ecosystem. Various
techniques including gas chromatography, electrochemical
methods, solid-phase micro-extraction-liquid chromatogra-
phy, ion mobility spectrometry, Raman spectroscopy and
fluorescence spectroscopy have been adopted for the detec-
tion of nitro explosives [24–28]. Of these methods, fluores-
cence is one of the preferred methods over others because
of its high sensitivity, selectivity, fast response and easy
sample preparation [1–6]. Fluorescent probes based on
pyrene, polycyclic aromatic derivatives, triphenylamine de-
rivatives, conjugated polymers, porphyrin derivatives and
Rhodamine derivatives have been investigated for selective
sensing of nitroaromatics [29–32]. Pang et al. recently re-
ported dansyl modified squaric dye for selective sensing of
PA [29]. BODIPY based fluorescent chemosensor was de-
veloped by Ravikanth et al. [33]. Nevertheless still it is a
great challenge to develop fluorescent sensor particularly
water soluble fluorescent probes.
Perylenediimides (PDI) are highly coloured organic dyes
with excellent optical properties such as high molar extinction
coefficients, fluorescence quantum yields and light harvesting
properties and outstanding thermal, chemical and photochemi-
cal stability that made them as potential materials for various
optoelectronic devices [34–37]. The excellent fluorescence
properties of PDIs have been utilized to develop fluorescent
probes for some metal cations and anions [38–46]. Nonetheless,
the growth of PDIs as fluorescent probes for sensing applica-
tions are relatively slow compared to Rhodamine and
coumarine based dyes that could be due to poor water solubility.
Moreover, the strong fluorescent PDIs have never been used as
fluorescent probe for detecting explosive NACs. In this manu-
script, we report the selective fluorescence sensing of picric acid
for the first times to the best our knowledge, PDI fluorescent
dyes have been used for selective sensing of NACs in water and
organic solvents.
Experimental Section
Perylenetetracarboxylic-3,4,9,10-bisanhydride and 2-N,N
′-dimethylaminoethylenediamine were received from
Sigma-Aldrich and used as without further purification.
N,N′-bis(dimethylaminoethyl)-perylene-3,4,9,10-
t e t r a c a r b o x y l i c b i s i m i d e ( P D I - 1 a ) , N , N ′ -
bis(ethelenetrimethylammoniumiodide)-perylene-3,4,9,
10-tetracarboxylicbisimide (PDI-1) and N,N′-bis(octyl)-
perylene-3,4,9,10-tetracarboxylicbisimide was synthe-
sized according to the reported procedure [47]. FT- IR
spectra for the synthesized compound was measured and
compared with the reported literature to confirm the
formation of PDI compounds. Absorption and fluores-
cence spectra were recorded using Perking Elmer Lamb-
da 1050 and Jasco fluorescence spectrometer-FP-8200
instruments. FT-IR spectra were measured using a
Shimadzu IRAffinity-1S spectrophotometer with KBr
pellets.
Synthesis of N,N′-bis(Dimethylaminoethyl)-Perylene-3,
4,9,10-Tetracarboxylicbisimide (PDI-1a) [47]
In atypical procedure, perylenetetracarboxylic-3,4,9,10-
bisanhydride (2 g, 5 mmol), quinoline 15 ml, and 2-N,N′-
dimethylaminoethylenediamine (20 mmol) and
dicyclohexylcarbodiimide (0.7 g, 3.4 mmol) were refluxed
with stirring in an inert atmosphere at 230–240 °C for 3–4 h.
After cooling to room temperature, the reaction mixture was
poured into 200 ml of ethanol. The resultant precipitate was
filtered and dried. The yield was 80 %. IR: ν (cm-1)=3016,
2958, 1699, 1652, 1592, 1571, 1508, 1443, 1270.
(PA) and 4-nitroaniline (4-NA) using PDI fluorophore salt, N,
N′-bis(ethelene trimethylammoniumiodide)-perylene-3,4,9,10-
tetracarboxylicbisimide (PDI-1) in organic as well as aqueous
medium across wide pH range (1.0 to 10.0). Addition of PA and
Synthesis of N,N′-bis(Ethelenetrimethylammoniumiodide)
-Perylene-3,4,9,10-Tetra-Carboxylicbisimide (PDI-1)
4-NA selectively quenches the fluorescence of PDI-1. The con-
centration dependent studies suggest that PDI-1 can detect PA
and 4-NA up to 1 μM. The interference studies demonstrated
high selectivity of PDI-1 for PA and 4-NA and other NACs did
not have significant influence. Interestingly, PDI-1 showed
strong fluorescence and selective fluorescence sensing of PA
and 4-NA across wide pH range (1.0 to 10.0). To get the insight
on the fluorescence sensing, trifluoroacetate (PDI-2), sulfate
Methyl iodide (10 mmol) was added into toluene (80 ml) so-
lution of PDI-1a (2.5 mmol) and refluxed with vigorous stir-
ring for 90 min. After cooling to room temperature, the pre-
cipitate was filtered, washed with ether and dried. The yield
was 88 %. IR: ν (cm-1)=3485, 3010, 2957, 1700, 1656, 1590,
1576, 1560, 1501, 1441, 1402, 1268.
(PDI-3) and octyl chain substituted PDI (PDI-4) with amine
Synthesis of N,N′-di(Octyl)-Perylene-3,4,9,
functionality have also explored for fluorescence sensing of
NACs which also showed selective sensing of PA and 4-NA.
These studies indicate that there might be selective and pre-
ferred interaction of PDI aromatic core with PA/4-NA. Thus,
10-Tetracarboxylicbisimide (PDI-4)
In a 50 mL round bottom flask, perylene-3,4,9,10-
tetracarboxylic dianhydride, (0.784 g, 2 mmol), 1-

J Fluoresc
octylamine (0.516 g, 4 mmol) and imidazole (4 g) were added
and refluxed at 140 °C for 3 h. The reaction mixture was
cooled to room temperature and dispersed in 100 ml of ethanol
followed by addition of 300 ml of 2 M HCl. The mixture was
stirred overnight. The resulting dark-red solid was filtered off
and washed thoroughly with distilled water followed by meth-
anol. The collected solid was dried under vacuum. The yield
was 75 %. IR: ν (cm-1)=3017, 2959, 1671, 1650, 1591, 1575,
Results and Discussion
PDI derivative of dimethylamine (PDI-1a) is highly insoluble
in most of the solvent and showed very weak fluorescence in
aqueous solution (0.06 M NaOH and 0.05 M detergent (SDS)
[47]. However, conversion dimethyl amine to trimethyl am-
monium iodide salt (PDI-1, Scheme 1) increased the solubility
in different solvent (DMF, DMSO) including water and ex-
hibited strong fluorescence. PDI-1 showed fluorescence
1
502, 1271.
Scheme 1 Synthetic scheme and
molecular structure of PDI
fluorophores (PDI-1 to PDI-4)

J Fluoresc
quantum yield of 0.26 (DMF) compared to fluorescein. PDI-1
has also showed good fluorescence in water. Fluorescence
sensing of PDI-1 was explored by adding NACs such as (2-
nitroanilline (2-NA), 3-nitroanilline (3-NA), 2-nitroanilline
(
(
4-NA), 2, 4-dinitroanilline (2,4-DNT), trinitrotoluene
TNT), 4-nitrobenzoic acid (4-NBA), nitrobenzene (NB),
picric acid (PA) and 4-nitrophenol (4-NP)) and monitoring
the fluorescence change. PDI-1 in DMF showed fluores-
cence at 545 nm and a small hump at 580 nm. Interesting-
ly, addition of PA and 4-NA into DMF solution of PDI-1
strongly reduces the fluorescence intensity both at 545 and
5
80 nm (Fig. 1). The fluorescence intensity of PDI-1 was
reduced by 4–6 times by addition of PA and 4-NA. Other
NACs did not significantly quench the PDI-1 fluorescence.
Excitation spectra were recorded to get the insight on the
selective fluorescence quenching of PDI-1 by PA and 4-NA
(
3
Fig. S1). The excitation spectrum of PDI-1 showed peak at
70, 465, 490 and 520 nm. Addition of PA and 4-NA leads
to selective disappearance of peak at 370 nm. Nevertheless,
other peaks are observed clearly. Other NACs addition did
not show any change in the excitation spectra of PDI-1.
These studies clearly suggest that PA and 4-NA might se-
lectively interact with PDI-1 aromatic core. The concentra-
tion dependent studies of PDI-1 for PA and 4-NA showed
linear decrease of fluorescence intensity (Fig. 2). This study
indicate that PDI can detect both PA and 4-NA easily up to
1
.0 μM. Interference studies were performed to explore the
influence of the other NACs on the detection of PA and 4-
NA by PDI-1 (Fig. 3). The interference studies confirmed
high selectivity and other NACs had little influence on the
sensing of PA and 4-NA.
Fig. 2 The change of PDI-1 fluorescence intensity with concentration of
PA (a) and 4-NA (b) in DMF
The fabrication of salt form of PDI makes it soluble in water.
Importantly, PDI-1 in water also showed good fluorescence. PA
is highly water soluble, hence it would be interesting to develop
PA sensor in aqueous medium. PDI-1 in water exhibited fluo-
rescence λmax at 548 nm and a small hump at 580 nm. Addition
of PA and 4-NA into aqueous solution of PDI-1 also selectively
quenched the fluorescence (Fig. 4). As observed in DMF, other
NACs addition did not show any significant influence on the
PDI-1 fluorescence. In aqueous medium, PDI-1 fluorescence
intensity was quenched by 10 times with addition of PAwhere-
as 4-NA addition reduces fluorescence intensity by 6 times.
PDI excitation spectra along with different NACs were record-
ed to get the insight on the selective fluorescence quenching of
PDI-1 by PA and 4-NA (Fig. S2). The excitation spectrum of
PDI-1 in water showed peak at 370, 490 and 540 nm. As ob-
served in DMF, addition of PA and 4-NA leads to selective
disappearance of peak at 370 nm. It is noted that apart from
complete disappearance of 370 nm peak, PA addition reduces
the intensity at 490 and 540 nm. However, addition of other
Fig. 1 Digital images and fluorescence spectra of PDI-1 with different
NACs in DMF

J Fluoresc
Fig. 4 Digital images and fluorescence spectra of PDI-1 with different
NACs in water
challenging since most of the fluorophore exhibit strong fluo-
rescence either at neutral/acidic/basic medium only. This
might be due to the change of electronic structure upon
addition/removable of proton by the change of pH. PDI-1 is
soluble in water across wide pH range (1.0 to 10.0). Interest-
ingly, it exhibit relatively steady fluorescence at pH 1.0 to 10.0
(Fig. S4). It is noted that PDI-1 showed slightly stronger fluo-
rescence at lower pH compared to basic medium. The above
fluorescence sensing experiment in water has performed at
neutral pH. Interestingly, addition of PA and 4-NA into aque-
ous solution of PDI-1 at pH 1.0, 3.0, 8.0 and 10.0 showed
selective fluorescence quenching (Fig. 6 and S5). However,
other NACs did not show significant influence on the PDI-1
fluorescence. The fluorescence intensity reduction was nearly
same at all pH solution. Thus, this study demonstrates that
PDI-1 can be used for selective sensing of PA and 4-NA
across wide pH range.
To study the effect of anions in PDI-1, trifluoro acetate and
sulfate salt of PDI was prepared in-situ from PDI-1a and fluo-
rescence sensing was investigated. Trifluoro acetate (PDI-2)
salt was prepared by adding trifluoroacetic acid (2 mole ratio)
into PDI-1a (1 mole) powder mixed in DMF. Similarly, sulfate
(PDI-3) salt was prepared by adding sulfuric acid (1 mole
ratio) into PDI-1a powder stirred in DMF. In both cases, the
insoluble PDI-1a was converted to soluble form that produced
clear solution. Similar to PDI-1, both PDI-2 and PDI-3
showed strong fluorescence in DMF. PDI-2 showed fluores-
cence λmax at 543 nm. Addition of PA and 4-NA selectively
quenches the fluorescence of PDI-2 (Fig. S6). As observed
with PDI-1, other NACs did not show any significant fluores-
cence quenching. The concentration dependent studies of
−
6
Fig. 3 Selectivity studies of PDI-1 for (a) PA nd (b) 4-NA (10 M) in
presence of other NACs (10− M) in DMF
3
NACs did not show any significant change in the PDI-1 exci-
tation spectra. These studies again indicate that PA and 4-NA
might selectively interact with PDI-1 aromatic core. In water,
PA might have stronger interaction with PDI-1 relative to 4-
NA. The concentration dependent studies of PDI-1 for PA and
4
-NA were performed to observe the change of fluorescence
with concentration and calculate the limit of detection. PDI-1
fluorescence intensity was linearly decreased with increased
addition of PA/4-NA from 0.1 to 1.0 μM (Fig. S3). It is noted
that 4-NA addition quenches the PDI-1 fluorescence relatively
stronger in DMF whereas PA quenches strongly in water. The
interference studies of PDI-1 indicate the high selectivity for PA
and 4-NA (Fig. 5). The interference studies suggest that other
NACs did not have significant influence on the sensing of PA
and 4-NA.
Developing fluorescence chemosensor that can selectively
detect NACs across wide pH range are highly interesting and

J Fluoresc
−6
Fig. 6 Fluorescence spectra of PDI-1 with different NACs in water at pH
(a) 1.0 and (b) 10.0
Fig. 5 Selectivity studies of PDI-1 for (a) PA nd (b) 4-NA (10 M) in
presence of other NACs (10−3 M) in water
nearly same fluorescence intensity from acidic to basic medi-
um. The fluorescence of PDI-1 was quenched by the addition
of PA and 4-NA across wide pH range (1.0 to 10.0). This
study suggests that selective NACs sensing of PDI-1 might
not be due to the formation of supramolecular system via H-
bond interactions. Since at basic condition, hydroxyl proton of
PA would be deprotonated completely whereas at acidic me-
dium it will be completely protonated that might modulate the
H-bonding formation between PDI-1 and NACs. This further
ruled-out any H-bonding interaction between the carbonyl
group of PDI-1 and NACs. PDI-4 that has only alkyl groups
without any ionic functionality has also showed similar selec-
tive fluorescence quenching for NACs. Hence PA and 4-NA
might be forming selective electrostatic interaction with PDI
aromatic core that quenches the fluorescence. The selective
fluorescence sensing of PDI-1 for NACs in different water
samples (tap, pond and ground water) demonstrate the practi-
cal applicability of PDI-1 for NACs sensing (Fig. S11).
PDI-2 exhibited decrease of fluorescence intensity linearly
with the concentration of PA and 4-NA (Fig. S7). PDI-2 also
showed the detection limit of 1 μM for PA and 4-NA. The
interference studies demonstrate the high selectivity for PA
and 4-NA in presence of other NACs (Fig. S8). PDI-3 has
also showed selective fluorescence quenching for PA and 4-
NA only (Fig. S9). To get the insight on the fluorescence
quenching of PDI salts, PDI derivative with alkyl group
(
PDI-4) has been prepared. Strong fluorescence was observed
for PDI-4 when dissolved in tetrahydrofuran (THF). NACs
sensing studies showed selective fluorescence quenching of
PDI-4 by PA and 4-NA only. As observed with other PDIs,
addition of other NACs did not show significant fluorescence
quenching. These studies indicate that substitutional group at
imide nitrogen whether it is hydrophilic amine salt function-
ality or hydrophobic alkyl chain did not show significant
change in fluorescence sensing of PDI dyes. PDI-1 showed

J Fluoresc
1
1
2. Zhang S, Fan J, Zhang S, Wang J, Wang X, Du J, Peng X (2014)
Chem Commun 50:14021
3. Wang Y, La A, Ding Y, Liu Y, Lei Y (2012) Adv Funct Mater 22:
Conclusion
In conclusion, highly selective fluorescence sensing of PA and
3
547
4
-NA has been demonstrated using perylenediimide based
14. Ju K-S, Parales RE (2010) Mol Biol Rev 74:250
1
1
1
5. Akhavan J (2011) The chemistry of explosives, 3rd edn. Royal
Society of Chemistry, Cambridge
6. Muthurajan H, Sivabalan R, Talawar MB, Asthana SN (2004) J
Hazard Mater 112:17
fluorophore salts, (PDI-1 – PDI-3) and octyl chain attached
PDI (PDI-4), in organic and aqueous medium. The strong
fluorescence of PDI-1 in DMF was selectively quenched by
the addition of PA and 4-NA. PDI-1 in water also showed
selective fluorescence sensing of PA and 4-NA. The concen-
tration dependent studies of PDI-1 showed decrease of fluo-
rescence intensity linearly with increase of PA and 4-NA con-
centration. The detection limit of PA and 4-NA by PDI-1 is
7. Volwiler EH (1926) Ind Eng Chem 18:1336
18. Bhalla V, Arora H, Singh H, Kumar M (2013) Dalton Trans 42:969
1
9. Zhang S, Ding L, Lü F, Liu T, Fang Y (2012) Spectrochim Acta A
7:31
9
2
0. Wyman JF, Serve MP, Hobson DW, Lee LH, Uddin J (1992) Safety
data sheet for picric acid, resource of National Institute of Health.
Toxicol Environ Health Part A 37:313
1
μM. The interference studies confirmed the high selectivity
2
2
1. Pimienta V, Etchenique R, Buhse T (2001) J Phys Chem A 105:
of PDI-1 for PA and 4-NA. Interestingly, PDI-1 exhibited
nearly same fluorescence intensity across wide pH range
1
0037
2. Shen J, Zhang J, Zuo Y, Wang L, Sun X, Li J, Han W, He R (2009) J
Hazard Mater 163:1199
(
1.0 to 10.0). Importantly, PDI-1 showed selective fluores-
cence sensing of PA and 4-NA at pH 1.0 to 10.0. The fluores-
cence sensing studies of trifluoroacetate (PDI-2), sulfate (PDI-
23. Shanmugaraju S, Joshi SA, Mukherjee PS (2011) J Mater Chem 21:
9130
2
2
4. Albert KJ, Wal DR (2000) Anal Chem 72:1947
5. Rose A, Zhu ZG, Madigan CF, Swager TM, Bulovic V (2005)
Nature 434:876
3
) salt and octyl chain attached derivative (PDI-4) has also
showed selective fluorescence sensing of PA and 4-NA. These
controlled studies suggest that there could be selective inter-
action between PDI core and PA/4-NA and substitutional
group at imine position might not play significant role in sens-
ing. Thus, water soluble highly fluorescent PDI dyes have
been employed for selective sensing of explosive NACs both
in organic and aqueous medium.
2
6. Monteil-Rivera F, Beaulieu C, Deschamps S, Paquet L, Hawari J
(2004) J Chromatogr A 1048:213
2
2
2
7. Charles PT, Kusterbeck AW (1999) Biosens Bioelectron 14:387
8. Desmet C, Blum LJ, Marquette CA (2012) Anal Chem 84:10267
9. Xu Y, Li B, Li W, Zhao J, Sun S, Pang Y (2013) Chem Commun
4
9:4764
30. Meaney MS, McGuffin VL (2008) Anal Chim Acta 610:57
3
3
1. Bhalla V, Gupta A, Kumar M, Rao DSS, Prasad SK (2013) ACS
Appl Mater Interfaces 5:672
2. Peng Y, Zhang A-J, Dong M, Wang Y-W (2011) Chem Commun
Acknowledgments Financial support from the Department of Science
and Technology, New Delhi, India (DST Fast Track scheme no. SR/FT/
CS-03/2011(G), SB/FT/CS-182/2011) is acknowledged with gratitude.
We thank CRF, SASTRA University for UV-Visible spectrophotometer.
The authors gratefully acknowledge the modern lab facility by Karunya
University.
4
7:4505
33. Madhu S, Bandela A, Ravikanth M (2014) RSC Adv 4:7120
34. Wurthner F (2004) Chem Commun, 1564
35. Huang C, Barlow S, Marder SR (2011) J Org Chem 76:2386
3
3
3
3
6. Ahrens MJ, Fuller MJ, Wasielewski MR (2003) Chem Mater 15:
684
7. Schmidt-Mende L, Fechtenkotter A, Mullen K, Moons E, Friend
RH, MacKenzie JD (2001) Science 293:1119
8. Marcia M, Singh P, Hauke F, Maggini M, Hirsch A (2014) Org
Biomol Chem 12:7045
9. He X, Liu H, Li Y, Wang S, Li Y, Wang N, Xiao J, Xu X, Zhu D
2
References
1
.
McDonagh C, Burke CS, MacCraith BD (2008) Chem Rev 108:
00
4
(2005) Adv Mater 17:2811
2
3
.
.
Valeur B, Leray I (2000) Coord Chem Rev 205:3
Qian X, Xiao Y, Xu Y, Guo XF, Qian J, Zhu W (2010) Chem
Commun 46:6418
4
4
0. Feng LH, Chen ZB (2007) Sens Actuators, B 122:600
1. Ruan Y-B, Li A-F, Zhao J-S, Shen J-S, Jiang Y-B (2010) Chem
Commun 46:4938
4
.
Kobayashi H, Ogawa M, Alford R, Choyke PL, Urano Y (2010)
Chem Rev 110:2620
42. Li J, Wu Y, Song F, Wei G, Cheng Y, Zhu C (2012) J Mater Chem
22:478
43. Wang B, Wang F, Jiao H, Yang X, Yu C (2010) Analyst 135:1986
44. Feng X, An Y, Yao Z, Li C, Shi G (2012) ACS Appl Mater
Interfaces 4:614
5
6
7
8
9
.
.
.
.
.
Kim JS, Quang DT (2007) Chem Rev 107:3780
Nolan EM, Lippard SJ (2009) Acc Chem Res 42:193
Kim HN, Ren WX, Kim JS, Yoon J (2012) Chem Soc Rev 41:3210
Anthony SP (2012) Chem Asian J 7:374
Liu Z, Qi Y, Guo C, Zhao Y, Yang X, Pei M, Zhang G (2014) RSC
Adv 4:56863
45. Ajayakumar MR, Mukhopadhyay P, Yadav S, Ghosh S (2010) Org
Lett 12:2646
1
1
0. Hariharan PS, Anthony SP (2014) RSC Adv 4:41565
1. Dhanunjayarao K, Mukundam V, Venkatasubbaiah K (2014) J
Mater Chem C 2:8599
46. Singh P, Mittal LS, Vanita V, Kumar R, Bhargava G, Wali A,
Kumar S (2014) Chem Commun 50:13994
47. Deligeorgiev T, Zaneva D, Petkov I (1994) Dyes Pigments 24:75